SMC Jack, 50 Ohm, 4 GHz — Through-Hole RF Termination
The 903-420J-52P: The threaded coupling gives a secure, vibration-resistant mate — the SMC interface is smaller than SMA but shares the same 50 Ohm impedance and 1/4-36 thread pattern, so it mates with standard SMC plugs. Insertion loss holds at 0.3 dB through the band, supported by the PTFE dielectric and gold-plated centre contact. The brass body carries a gold finish, and the contact is terminated by soldering through the PCB hole.
The 4 GHz frequency ceiling is the upper limit where the connector maintains its specified VSWR and insertion loss; beyond that, the interface geometry starts to radiate. For designs operating below 4 GHz, the 0.3 dB insertion loss is tight enough that it won't eat into the link budget. The gold-on-gold contact interface (centre contact and body finish both gold) keeps the RF path clean and resists corrosion in humid or outdoor enclosures.
Mating and Termination — Through-Hole Solder, Threaded Coupling
The threaded fastening locks the mated pair; the PTFE dielectric handles -65°C to 165°C.